Some of you will remember my ongoing project gun which I dubbed the "Hayabusa".... It has been through three versions, the Mark I was a regulated repeater shooting pellets in .22 and .25 cal, the Mark II was an unregulated version built for bullets in four calibers, .224, .257, .308, and .357, and the Mark III, completed a few months ago, was also unregulated, in .410 shotgun and .458 rifle versions.... I decided some time ago that the 7mm (.284) caliber had some advantages in long range ballistics over the .257 and .308 as a varmint rifle, and finally got a .284 liner with a 14" twist from TJ's and I have on order a 94 gr. Bob's Boattail bullet mold from Veral at LBT which will be sent to Erik at HollowPoint Service to have two of the four cavities converted to HP.... I have been collecting the parts for a while now, and today was the day to start making chips.... Here is the beginnings of the new breech, with the bottom rebate for the main tube machined....



The rifle will be built on the Mark II version, using the larger valve which was designed for the .308 and .357.... The valve has a 9/32" exhaust port and the throat is over 5/16", so the porting when used with the 7mm barrel will be full bore area to maximize the power possible.... I will even be using a probeless, retracting bolt to avoid any restriction to the airflow, the idea borrowed from my Disco Double which was the first gun I built to utilize that feature.... I originally planned to use the .308/.357 breech, but with the change to the retracting bolt, and some other changes I have planned for this build, a new breech became necessary....

Bob